Maresca's men roared back from a 1-0 half-time deficit to thrash Real Betis 4-1 on Wednesday to collect their first trophy since an American consortium bought the club from former owner Roman Abramovich in 2022.
Victory in Wroclaw rounded off a fine first season in charge for Maresca after also securing a return to the Champions League next season by finishing fourth in the Premier League.
Chelsea captain Reece James conceded anything other than winning Europe's third-tier competition would have been perceived as a failure given the English giants' financial advantage. In the three years since the consortium, fronted by LA Dodgers co-owner Todd Boehly and private equity group Clearlake Capital, took over, Chelsea have splashed out over £1 billion ($1.4 billion) on transfer fees on young talent.
"The club invest lots of money in the last three or four years, so they are also waiting for results," Maresca told TNT Sports.
"Hopefully this can be a starting point and from tonight, from this season, (we are) building something important."
Victory also meant Chelsea became the first club to win all four major UEFA competitions after the Champions League, Europa League and disbanded Cup Winners' Cup.
"To be the only team in history (to win all four), it is a great feeling," said Cole Palmer, who helped turn the game with two assists for Chelsea's first two goals.